Why would a car cut off when a spark plug wire is removed when running?
Depends on the number of cylinders, when you remove the wire, you are essentially killing that one cylinder – if you only have 4 , then you have immediately killed 1/4 of the cylinders and at idle, the motor doesn’t have enough power to keep running – I would also bet that the other cylinders are getting weak spark check how old the spark plug wires are – they only last for a certain life and then crack and start giving trouble also your spark plugs might be worn and weak – so with one plug missing, there isnt enough fire to keep the motor running remove the plugs and look for worn electrodes and or soot on the tip of the plugs
